Something interesting happened to me after a brief period of being out of Epitalon. I know that some say to cycle it, but I don't think I can. I was without for about 10 days. Within that period, I had quite a slide back to worse than I was prior to starting. It mainly affected my sleep. I would sleep, if given the opportunity, for 12 hours and always awoke extremely tired. It was awful! I re-started yesterday and already I feel energized and my sleep is back to normal. I need to repeat this at some point to see if it was truly the Epitalon. I did just return from a very active vacation but I didn't have the normal "crash" until I ran out. So we'll see.